Re: [PATCH 1/7] ARM: tegra: finalize USB EHCI and PHY bindings

[Stephen Warren <swarren@wwwdotorg.org>]

On 03/20/2013 06:15 AM, Venu Byravarasu wrote:
>> -----Original Message-----
>> From: kishon [mailto:kishon@ti.com]
>> Sent: Wednesday, March 20, 2013 4:49 PM
>> To: Venu Byravarasu
>> Cc: gregkh@linuxfoundation.org; stern@rowland.harvard.edu;
>> balbi@ti.com; linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org;
>> swarren@wwwdotorg.org; linux-tegra@vger.kernel.org; devicetree-
>> discuss@lists.ozlabs.org
>> Subject: Re: [PATCH 1/7] ARM: tegra: finalize USB EHCI and PHY bindings
>>
>> Hi,
>>
>> On Monday 18 March 2013 05:59 PM, Venu Byravarasu wrote:
>>> The existing Tegra USB bindings have a few issues:
>>>
>>> 1) Many properties are documented as being part of the EHCI controller
>>> node, yet they apply more to the PHY device. They should be moved.
>>>
>>> 2) Some registers in PHY1 are shared with PHY3, and hence PHY3 needs a
>>> reg entry to point at PHY1's register space. We can't assume the PHY1
>>> driver is present, so the PHY3 driver will directly access those
>>> registers.
>>>
>>> 3) The list of clocks required by the PHY was missing some required
>>> entries.
>>>
>>> This patch fixes the binding definition to resolve these issues.
>>>
>>> Signed-off-by: Venu Byravarasu <vbyravarasu@nvidia.com>
>>> ---
>>>   .../bindings/usb/nvidia,tegra20-ehci.txt           |   27 +++----------------
>>>   .../bindings/usb/nvidia,tegra20-usb-phy.txt        |   27
>> +++++++++++++++++--
>>>   2 files changed, 29 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
>> b/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
>>> index 34c9528..df09330 100644
>>> --- a/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
>>> +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra20-ehci.txt
>>> @@ -6,27 +6,10 @@ Practice : Universal Serial Bus" with the following
>> modifications
>>>   and additions :
>>>
>>>   Required properties :
>>> - - compatible : Should be "nvidia,tegra20-ehci" for USB controllers
>>> -   used in host mode.
>>> - - phy_type : Should be one of "ulpi" or "utmi".
>>>
>>>   Optional properties:
>>> -  - dr_mode : dual role mode. Indicates the working mode for
> 
>>> index 6bdaba2..7ceccd3 100644
>>> --- a/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt
>>> +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt
>>> @@ -4,8 +4,24 @@ The device node for Tegra SOC USB PHY:
>>>
>>>   Required properties :
>>> + - phy_type : Should be one of "utmi", "ulpi" or "hsic".
>>
>> dt property names generally dont have "_".
> 
> Thanks Kishon, for your comments.
> Is it mandatory or optional?
> If it is mandatory, then I might have to change dr_mode as well along with phy_type.

This rule is basically mandatory for *new* property definitions.

However, both phy_type and dr_mode are properties that already exist and
have historical precedence for their naming. So, I don't think we can
change them. In fact, IIRC, someone even posted some patches to provide
a common set of parsing functions for those properties, and I assume
those patches use the existing names with _ in them. The patches aren't
applied yet though, I think.

(Venu, we already discussed this rule downstream)